Fear Allah and say "Allah is the Greatest" upon every elevated place
Good hadithعن أبي هريرة رضي الله عنه : أنّ رجلًا قال: يا رسول الله، إني أُريد أن أُسافرَ فأَوْصِني، قال: «عليك بتقوى الله، والتَّكبير على كلِّ شَرَفٍ» فلمّا ولَّى الرجلُ، قال: «اللهم اطْوِ له البُعدَ، وهَوِّنْ عليه السفر».
Abu Hurayrah (may Allah be pleased with him) reported that a man said: "O Messenger of Allah, I want to set out on a journey, so advise me." He said: "Fear Allah and say 'Allah is the Greatest' upon every elevated place." When the man turned away, he (the Prophet) said: "O Allah, make the distance short for him and make the journey easy for him.”
Explanation
A man intended to travel so he asked the Messenger of Allah (may Allah's peace and blessings be upon him) to advise him. The Prophet (may Allah's peace and blessings be upon him) advised him to adhere to God-consciousness and to say "Allah is the Greatest " upon every high place. When the man turned away, the Prophet (may Allah's peace and blessings be upon him) asked Allah to grant him the required energy and the good mount that would make him reach his destination easily, and to facilitate his journey by removing harms away from him.
Source · Narrated by Ibn Majah - Narrated by At-Termedhy - Narrated by Ahmad
From the Hadith Encyclopedia (hadeethenc.com).